Herbicidal sulfonylureas, their preparation and use

Details Herbicidal sulfonylureas, their preparation and use Herbicidal sulfonylureas, their preparation and use

2000-03-07

2001-11-20

Ford, John M. (Department: 1624)

Organic compounds -- part of the class 532-570 series

Organic compounds

Four or more ring nitrogens in the bicyclo ring system

Reexamination Certificate

active

06320046

ABSTRACT:

The present invention relates to sulfonylureas of the general formula I
where
R
1
is a methyl or ethyl group;
R
2
is C
1
-C
3
-alkoxycarbonyl, a C
1
-C
2
-alkyl group which carries 1 to 5 fluorine atoms, methylsulfonyl, dimethylaminosulfonyl, thiomethyl, methylsulfinyl, methylsulfonyloxy, trifluoromethoxy, difluoromethoxy, difluorochloromethoxy, difluorochloromethyl or nitro;
R
3
is hydrogen, methyl, methoxy, ethoxy, fluorine, chlorine or thiomethyl;
W is hydrogen or chlorine and
Z is CH or N
and their agriculturally utilizable salts.
In U.S. Pat. No. 4,120,691, the nearest structures described are the triazine compound A and the pyrimidine derivative B (cf. also U.S. Pat. No. 4,169,719).
In EP-A 48 808, sulfonylureas D having a substituent in the aromatic moiety are described.
In EP-A 48 143, two N-methylated sulfonylureas E are shown without closer characterization.
EP-A 388 873 covers benzoic acid esters of the structure F.
In U.S. Pat. No. 4,310,346, sulfonamides of the type G are listed.
German Laid-Open Application DE-OS 40 38 430 (WO 92/09608) describes trifluoromethyl-substituted triazines of type H.
EP-A 120 814 mentions the compound J without details of physical data.
It is an object of the present invention to synthesize sulfonylureas which, compared with the known representatives of this class of herbicide, have improved properties and are particularly distinguished by high selectivity in sensitive crops.
We have now found that this object can be achieved by the sulfonylureas of the formula I defined at the outset.
In the formula I, C
1
-C
3
-alkoxycarbonyl is methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl or isopropoxycarbonyl and a C
1
-C
2
-alkyl group which carries 1 to 5 fluorine atoms is methyl, substituted by 1 to 3 fluorine atoms, or ethyl, substituted by 1 to 5 fluorine atoms, eg. trifluoromethyl, difluoromethyl, 2,2,2-trifluoroethyl or 1,1,2,2-tetrafluoroethyl.
Sulfonylureas of the formula I are particularly preferred in which R
2
is methoxycarbonyl, trifluoromethyl, dimethylaminosulfonyl, trifluoromethoxy, difluoromethoxy or methylsulfonyl, and also sulfonylureas having a triazine substituent (Z═N). Compounds I with difluoromethyl substitution of hetero atoms (W═H) are additionally particularly important.
The sulfonylureas of the formula I according to the invention are accessible by various routes which are described in the literature. By way of example, particularly advantageous routes (A-C) may be illustrated in greater detail in the following.
A: A sulfonyl isocyanate II is reacted in a manner known per se (EP-A-162 723) with approximately the stoichiometric amount of a 2-amino-1,3,5-triazine or 2-aminopyrimidine derivative III at from 9 to 120° C., preferably from 10 to 100° C. The reaction can be carried out continuously under normal pressure or under pressure (up to 50 bar), preferably at from 1 to 5 bar.
Inert solvents and diluents are expediently used for the reactions under the respective reaction conditions. Suitable solvents are, for example, halohydrocarbons, in particular chlorohydrocarbons, eg. tetrachloroethylene, 1,1,1,2- or 1,1,2,2-tetrachloroethane, dichloropropane, methylene chloride, dichlorobutane, chloroform, chloronaphthalene, dichloronaphthalene, carbon tetrachloride, 1,1,1- or 1,1,2-trifluoroethane, trichloroethylene, pentachloroethane, o-, m- or p-difluorobenzene, 1,2-dichloroethane, 1,1-dichloroethane, 1,2-cis-dichloroethylene, chlorobenzene, fluorobenzene, bromobenzene or iodobenzene, o-, m- or p-dichlorobenzene, o-, p- or m-dibromobenzene, o-, m- or p-chlorotoluene, 1,2,4-trifluorobenzene; ethers, eg. ethyl propyl ether, methyl tert-butyl ether, n-butyl ethyl ether, di-n-butyl ether, diisobutyl ether, diisoamyl ether, diisopropyl ether, anisole, phenetole, cyclohexyl methyl ether, diethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, dioxane, thioanisole or &bgr;,&bgr;′-dichlorodiethyl ether, nitrohydrocarbons such as nitromethane, nitroethane, nitrobenzene, o-, m- or p-chloronitrobenzene or o-nitrotoluene; nitriles such as acetonitrile, butyronitrile, isobutyronitrile, benzonitrile or m-chlorobenzonitrile; aliphatic or cycloaliphatic hydrocarbons, eg. heptane, pinane, nonane, or o-, m- or p-cymene, benzene fractions within a boiling point range from 70 to 190° C., cyclohexane, methylcyclohexane, decalin, petroleum ether, hexane, naphtha, 2,2,4-trimethylpentane, 2,2,3-trimethylpentane, 2,3,3-trimethylpentane or octane; esters, eg. ethyl acetate, ethyl acetoacetate or isobutyl acetate; amides, eg. formamide, methylformamide or dimethylformamide; ketones, eg. acetone or methyl ethyl ketone, and suitable mixtures. The solvent is expediently used in an amount of from 100 to 2000% by weight, preferably from 200 to 700% by weight, based on the starting substance II.
The compound II required for the reaction is in general employed in approximately equimolar amounts (using an excess or deficit of eg. 0 to 20%, based on the respective starting substance III). The starting substance III can be introduced in one of the diluents mentioned and the starting substance II then added.
The process for preparing the novel compounds is expediently carried out, however, such that the starting substance II is introduced, if appropriate in one of the abovementioned diluents, and the starting substance III is then added.
To complete the reaction, the mixture is subsequently stirred after the addition of the components for a further 20 minutes to 24 hours at from 0 to 120° C., preferably from 10 to 100° C.
A reaction accelerator which can be used is advantageously a tertiary amine, eg. pyridine, &agr;, &bgr; or &ggr;-picoline, 2,4- or 2,6-lutidine, 2,4,6-collidine, p-dimethylaminopyridine, trimethylamine, triethylamine, tri(n-propyl)amine, 1,4-diaza[2.2.2]bicyclooctane [DABCO] or 1,8-diazabicyclo[5.4.0]undec-7-ene in an amount of from 0.01 to 1 mol per mole of starting substance II.
The final substance I is isolated from the reaction mixture in a customary manner, eg. by removal of solvent by distillation or directly by filtering off with suction. The residue which remains can additionally be washed with water or dilute acid to remove basic impurities. However, the residue can also be dissolved in a water-immiscible solvent and washed as described. The desired final substances are obtained here in pure form. If necessary they can be purified by recrystallization, stirring in an organic solvent which takes up the impurities or chromatography.
Preferably, this reaction is carried out in acetonitrile, methyl tert-butyl ether, toluene or methylene chloride in the presence of from 0 to 100 mol equivalents, preferably from 0 to 50 mol equivalents, of a tertiary amine such as 1,4-diazabicyclo[2.2.2]octane or triethylamine.
B: A sulfonamide of the formula IV is reacted in a manner known per se (EP-A 141 777 or EP-A 101 670) in an inert organic solvent with approximately the stoichiometric amount of a phenyl carbamate V and from 0 to 120° C., preferably from 20 to 100° C. The reaction can be carried out continuously or batchwise at normal pressure or under pressure (up to 50 bar), preferably at from 1 to 5 bar.
Bases such as tertiary amines can be added here which accelerate the reaction and improve the product quality. Suitable bases for this purpose are those indicated under A, in particular triethylamine, 2,4,6-collidine, 1,4-diazabicyclo[2.2.2]octane [DABCO] or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), in an amount of from 0.01 to 1 mol per mole of starting substance IV.
The solvents or diluents expediently used are those indicated under A.
The solvent is used in an amount of from 100 to 2000% by weight, preferably from 200 to 700% by weight, based on the starting material IV.
The compound IV required for the reaction is in general employed in approximately equimolar amounts (using an excess or deficit of eg. from 0 to 20%, based on the respective starting substances V). The starting substance V can be introduced into one of the abovementione

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